Ultra high frequency coupling circuit



Jun e 17, 1947. I D. R. TASHJIAN I 2,422,601

ULTRA HIGH FREQUENCY COUPLING CIRCUIT .Filed May 20, 1943 /a I I /a' WITNESSES: INVENTOR ATTORNEY Patented June 17, 1947 ULTRA HIGH FREQUENCY COUPLING CIRCUIT David R. Tashjian, Baltimore, Md., assignor t Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application May 20, 1943, Serial No. 487,753

Claims.

This invention relates to high frequency transmission circuits and, particularly, to coupling systems for the distribution of high frequency energy operating in the ultra high frequency portion of the spectrum.

A particular feature of the invention is that in a distribution system for high frequency energy'by means of coaxial transmission lines, distribution of high frequency, current may be effected through various channels at will and to a desired degree.

Another feature of the invention is that by a single 'operationtwo transmission channels may be controlled to be effectively coupled to a main distribution junction and to be decoupled therefrom at will.

An advantage of the coupling-system is that high frequency energy may be transferred over an electromagnetic loop which is part of the transmission line and may be-oriented easily in any desired 'manneras to degree of coupling.

Another advantage of the invention is that two feeders of'the coupling system may be controlled simultaneously in such manner that energy can'be'transferred from one feeder to a desired point of transmission without interfering with the other feeder and vice versa. By simple operation the direction of current transmission may be reversed from the point of transmission aforementioned to one of the feeders.

Other features and advantages will be apparent from the following description of "the invention, pointed out in particularity by the appended claims and'taken'in connection with the accompanying drawing, in which the figure shows a sectional view of a high frequency coupling circuit constructed in accordance with the invention.

In communication systems operating at frequencies above several hundred megacycles the problem of providing an efficientand low capacity transfer circuit becomes increasingly difficult. It is often desirable to connecttransmission lines in such manner as torform a junction whereby ultra high frequency energy can be effectively distributed with aminimum amount of loss to various channels. It is particularly-desirable in certain systems that transmission of ultra high frequency energy be efficiently and simply controlled through a number of channels in such manner that the path of high frequency current may be conveniently switched from one to another.

The coupling system herein described provides means whereby high frequency energy may be directed in a confined path such as a concentrio transmission line in any desired direction. The invention as illustrated shows the application of the principle of operation to a high frequency junction in which it is desired to couple two transmission lines to a third line in such manner that at one setting maximum coup-ling will be effected between one line and the third line, and at the same time minimum coupling between .the third line and the second line. The coupling can be alternately changed between the two lines to the third line by simple operating means. The type of operation referred to is particularly useful when a transmitter and a receiver are conjointly operated from a single antenna, and it is necessary to prevent energy transferto the .receiver while the transmitter is in operation, and vice versa, to prevent interferonce from the transmitter when the receiver is in operation.

Referring to the drawing, the portion of the concentric transmission line lis coupled to a junction -2 comprising also a transmission line; both lines include a concentric housing or shell 3 and 3 and an inner conductor 4 and 4. Concentric lines of this type are well known in the art, and it is understood that the inner conductors ar suitably spaced from the outersh'ell by means of insulating spacers not shownhere. The transmission line I iscoupled to the transmission line 2 in such manner that the inner conductor protrudes within the space of the transmission line 2 :and forms a loopt which is so oriented with respect to the conductor 4 as to permit maximum-energy transferbetween the inner conductors A and l. This is effected when the loop 5 is inductivelyso related that, it is substantially parallel to the innerconductor 4'. The latter may be supported bymeans of the spacerfi and sliding stubs l andl' which make electrical contact with the shell 3. The sliding stubs l and 7 are utilized to terminate the transmission line junctioni at suitable points for effecting coupling to the other lines as will be heretofore described. .To the junction line 2 is connected a pair'of transmission lines 8 and 8' eachccomprising asleeve 9 and 9', respectively, which are securely fastened to the shell 3 by means of bushings l0 and In, respectively, permitting rotation of the sleeve 9 and 9' within the bushings mentioned. The rotatable sleeve 9 is journalled in the shell ll of the transmission line 8 and similarly the sleeve 9' in the transmission line H. The inner conductors l3 and I3 of the lines 8 and 8, respectively, within the sleeve portion are secured to the inner wall of the sleeves 9 and 9' by means of suitable insulating spacers M and Hi and I and t5, respectively. The terminals protruding into the junction line is formed into a loop it and it which when the sleeve 9 or 9 is rotated will be so oriented with respect to the conductor 4 as to be in parallel therewith in one position and substantially at right angles thereto when rotated 90. While the sleeve 9 is rotated, the inner conductor l3 permits turning of the loop shaft by means of the coupling I8 which forms a bearing around the lower terminal of the looped conductor.

Rotation may be effected in a simple manner by gears and 20 around the sleeves 9 and 9, respectively, so arranged as to mesh with an intermediate pinion Zl which may be driven by the shaft 22 provided with a hand Wheel 23.

The expedient of rotating coupling loops within a transmission line as shown here intends to illustrate the application of the basic principle of the invention, namely, to distribute ultra-high frequency energy in a transmission line by means of simple loops formed by the inner conductor dis placeable with respect to the inner conductor of the junction line. Maximum flux linkage between conductor 4 and loops l6 and I6 is effected when the loops are in parallel with the conductor 4 and minimum flux linkage or substantially zero linkage when the loop It or i5 is perpendicular to the inner conductor 4.

Rotatable loops in concentric transmission lines form an effective coupling means in accordance with this invention and may be applied to various types of transmission circuits and in a great number of combinations to provide not only an emcient and simple energy transmission circuit but also to provide a flexible control of the amount of energy to be transferred to various points of the system. This is accomplished by rotating the loop to any desired point between zero and 90 and thereby adjusting the amount of energy transfer desired at the particular junction terminal.

I claim as my invention:

1. In a coupling circuit for ultra high frequency energy transmission, an energy transfer junction comprising a coaxial transmission line, a main coaxial feeder and a pair of auxiliary coaxial feeders terminating in said line, a fixed coupling between said feeder and said line comprising a loop oriented for maximum energy transfer, a variable coupling between each of said auxiliary feeders and said line comprising individual loops for each of said last mentioned feeders, and means for simultaneously orienting said loop in alternate order and in opposition effecting orientation for maximum coupling in one of said feeders and oriented for minimum coupling of the other of said feeders.

2. In an ultra high frequency coupling circuit, a coaxial line having a shell and an inner conductor, a main coaxial feeder connected to a portion of said line, a pair of auxiliary feeders each connected to another portion of said line, a fixed coupling between said main feeder and said line comprising a loop of the inner conductor of said main feeder oriented for maximum energy transfer with respect to the inner conductor of said line, a variable coupling for each of said auxiliary feeders comprising a loop terminating the inner conductors thereof, said last mentioned loops being rotatable for orientation with respect to the inner conductor of said line, and means for rotating said loops simultaneously for effectmg maximum and minimum couplings, respectively.

3. A coupling circuit in accordance with claim 2 in which said variable couplings comprise a rotatable shell portion of each of said feeders, an inner conductor concentric therewith and secured thereto by means of insulating supports, said inner conductor at one end being bent to form a loop protruding into the inner space of said line and the other end journalled in the inner conductor of the fixed portion of said shell.

4. A coupling circuit in accordance with claim 2 wherein each of said loops are effectively in electric contact with the shells.

5. In an ultra high frequency coupling circuit, a coaxial line having a shell and an inner conductor, a main coaxial feeder connected to a portion of said line,a pair of auxiliary feeders each connected to another portion of said line, a fixed coupling between said main feeder and said line comprising a loop of the inner conductor of said main feeder oriented for maximum energy transfor with respect to the inner conductor of said line, a variable coupling for each of said auxiliary feeders comprising a rotatable shell portion of each of said feeders, an inner conductor'concentric therewith and secured thereto by means of insulating supports, said inner conductor at one end being bent to form a loop protruding into the inner space of said line and the other end journalled in the inner conductor of the fixed portion of said shell, said last mentioned loops being rotatable for orientation with respect to the inner conductor of said line and spaced effectively at and means for rotating said loops simultaneously for effecting maximum and minimum couplings, respectively, comprising a gear secured to each rotatable portion and a driving gear meshed therewith whereby said gears are rotated in opposite directions.

DAVID R. TASHJIAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,281,274 Dallenbach et a1. Apr. 28, 1942 2,312,783 Trevor Mar. 2, 1943 2,311,520 Clifford Feb. 16, 1943 2,045,904 Furnival et al June 30, 1936 2,177,272 Zottu Oct. 24, 1939 2,189,549 Hershberger Feb. 6, 1940 OTHER REFERENCES Article in the Proceedings of the I. R, E., April 1940, entitled Natural Oscillations of Electrical Cavity Resonators, by W. L. Barrow and W. W. Mieher. (Copy in 250-39.2.) 

